DC/OS on Azure using the Universal Installer

Guide for DC/OS on Azure using the Mesosphere Universal Installer

To use the Mesosphere Universal Installer with Azure, the Azure command line interface must be installed and configured to the security credentials of the account you will be using for resources. The following instructions will guide you through the necessary account creation and credentials to be able to successfully configure your Azure CLI and install DC/OS.

Install and configure the Azure CLI

Install the Azure CLI guide to get az installed and running. For macOS users, it is available using Homebrew:

brew install azure-cli

Once you have the Azure CLI, it needs to be connected to the account you would like to use. If you already had the CLI installed, you may already have your credentials set up. To set up your credentials, or to update them anytime as needed, run:

az login

Follow any directions, including signing in from your browser, to enable your CLI.

You can insure that you are logged in by listing your account permissions:

Set the ARM_SUBSCRIPTION_ID. The current Terraform Provider for Azure requires that the default Azure subscription be set before terraform can start. provide the Azure subscription ID. You can set the default account with the following command:

export ARM_SUBSCRIPTION_ID="desired-subscriptionid"

As an example:

export ARM_SUBSCRIPTION_ID="12345678-abcd-efgh-9876-abc123456789"

Ensure it is set:

echo $ARM_SUBSCRIPTION_ID

Set up SSH credentials for your cluster

Terraform uses SSH key-pairs to connect securely to the clusters it creates. If you already have a key-pair available and added to your SSH-Agent, you can skip this step.

This starts an interactive process to create your key-pair. It will ask you to enter a location to store your keys. For example, to set up a new keypair in your .ssh directory:

Creating a DC/OS Cluster

Let’s start by creating a local folder and cd’ing into it. This folder will be used as the staging ground for downloading all required Terraform modules and holding the configuration for the cluster you are about to create.

mkdir dcos-tf-azure-demo && cd dcos-tf-azure-demo

Create a file in that folder called main.tf, which is the configuration file the Mesosphere Universal Installer will call on each time when creating a plan. The name of this file should always be main.tf.

touch main.tf

Open the file in the code editor of your choice and paste in the following. Notice the copy icon in the upper right hand corner of the code block to copy the code to your clipboard:

This sample configuration file will get you started on the installation of an open source DC/OS 1.12 cluster with the following nodes:

1 Master

2 Private Agents

1 Public Agent

If you want to change the cluster name or vary the number of masters/agents, feel free to adjust those values now as well. Cluster names must be unique, consist of alphanumeric characters, ‘-’, ‘_’ or ‘.’, start and end with an alphanumeric character, and be no longer than 24 characters. You can find additional input variables and their descriptions here.

There are also simple helpers listed underneath the module which find your public ip and specify that the following output should be printed once cluster creation is complete:

master-ips A list of Your DC/OS master nodes

cluster-address The URL you use to access DC/OS UI after the cluster is setup.

public-agent-loadbalancer The URL of your Public routable services.

Check that you have inserted your cloud provider and public key paths to main.tf, changed or added any other additional variables as wanted, then save and close your file.

Now the action of actually creating your cluster and installing DC/OS begins. First, initialize the project’s local settings and data. Make sure you are still working in the dcos-tf-azure-demo folder where you created your main.tf file, and run the initialization.

terraform init

Terraform has been successfully initialized!
You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.
If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your environment. If you forget, other
commands will detect it and remind you to do so if necessary.

Note: If terraform is not able to connect to your provider, ensure that you are logged in and are exporting your credentials. See the Azure Provider instructions for more information.

After Terraform has been initialized, the next step is to run the execution plan and save it to a static file - in this case, plan.out.

terraform plan -out=plan.out

Writing our execution plan to a file allows us to pass the execution plan to the apply command below as well help us guarantee the accuracy of the plan. Note that this file is ONLY readable by Terraform.

Afterwards, we should see a message like the one below, confirming that we have successfully saved to the plan.out file. This file should appear in your dcos-tf-azure-demo folder alongside main.tf.

Every time you run terraform plan, the output will always detail the resources your plan will be adding, changing or destroying. Since we are creating our DC/OS cluster for the very first time, our output tells us that our plan will result in adding 38 pieces of infrastructure/resources.

The next step is to get Terraform to build/deploy our plan. Run the command below.

terraform apply plan.out

Sit back and enjoy! The infrastructure of your DC/OS cluster is being created while you watch. This may take a few minutes.

Once Terraform has completed applying our plan, you should see output similar to the following:

And congratulations - you’re up and running!

Logging in to DC/OS

To login and start exploring your cluster, navigate to the cluster-address listed in the output of the CLI. From here you can choose your provider to create the superuser account Open Source, or login with your specified Enterprise credentials Enterprise.

Scaling Your Cluster

Terraform makes it easy to scale your cluster to add additional agents (public or private) once the initial cluster has been created. Simply follow the instructions below.

Increase the value for the num_private_agents and/or num_public_agents in your main.tf file. In this example we are going to scale our cluster from 2 private agents to 3, changing just that line, and saving the file.

num_masters = "1"
num_private_agents = "3"
num_public_agents = "1"

Now that we’ve made changes to our main.tf, we need to re-run our new execution plan.

terraform plan -out=plan.out

Doing this helps us to ensure that our state is stable and to confirm that we will only be creating the resources necessary to scale our Private Agents to the desired number.

You should see a message similar to above. There will be 3 resources added as a result of scaling up our cluster’s Private Agents (1 instance resource & 2 null resources which handle the DC/OS installation & prerequisites behind the scenes).

Now that our plan is set, just like before, let’s get Terraform to build/deploy it.

terraform apply plan.out

Once you see an output like the message above, check your DC/OS cluster to ensure the additional agents have been added.

You should see now 4 total nodes connected like below via the DC/OS UI.

Upgrading Your Cluster

Terraform also makes it easy to upgrade our cluster to a newer version of DC/OS. If you are interested in learning more about the upgrade procedure that Terraform performs, please see the official DC/OS Upgrade documentation.

In order to perform an upgrade, we need to go back to our main.tf and modify the current DC/OS Version (dcos_version) to a newer version, such as 1.12.1 for this example, and also specify an additional parameter (dcos_install_mode). By default this parameter is set to install, which is why we were able to leave it unset when creating the initial DC/OS cluster and scaling it.

IMPORTANT: Do not change any number of masters, agents or public agents while performing an upgrade.

dcos_version = "1.12.1"

Re-run the execution plan, temporarily overriding the default install mode by setting the flag to read in the extra variable.

terraform plan -out=plan.out -var dcos_install_mode=upgrade

You should see an output like below, with your main.tf now set for normal operations on a new version of DC/OS.

Apply the plan.

terraform apply plan.out

Once the apply completes, you can verify that the cluster was upgraded via the DC/OS UI.

Deleting Your Cluster

If you want to destroy your cluster, then use the following command and wait for it to complete.

terraform destroy

Important: Running this command will cause your entire cluster and all at its associated resources to be destroyed. Only run this command if you are absolutely sure you no longer need access to your cluster.